The ability of soluble cytokine receptors to alter the inflammatory responses to intravenous endotoxin will be evaluated in normal volunteers (Protocol 92-CC-0141). In a Phase I/II trial, soluble TNF receptor will be given intravenously to normal humans. The first phase of the study will evaluate the safety and pharmacokinetics of infused recombinant cytokine receptor. The second phase will evaluate the ability of the cytokine receptors to alter the inflammatory responses and changes in systemic hemodynamics that occur following intravenous endotoxin. Using selective inhibitors to proinflammatory cytokines will provide information regarding early host responses to bacterial products and provide additional scientific information for these new therapies in human septic shock.